Abstract

Wallenberg's syndrome is a neurological disorder usually caused by occlusion of postero-inferior cerebellar artery or vertebral artery. It's the most common ischemic event of the encefalic trunk and is characterized by misleading symptoms and signs.

When a young boy came to the Emergency Department (ED) with acute dizziness and anisocoria we performed a cranial CT (resulted negative) and we treated him with steroid therapy. We dismissed him at home with the diagnosis of suspected vestibular neuronitis. The day after he showed up again at the ED complaining dysphagia, dysphonia, ataxia and paresthesia of left face and right body.

Angio-CT (CTA) showed a intracranial left vertebral artery dissection and MRI a left bulbar ischemic lesion. He was treated with antiplatelet drugs and after a period of rehabilitation therapy he recovered almost completely.

Keywords

Introduction

Dizziness is one of the most common presentations to the Emergency Department: it occurs in about 20-30% of population, with a prevalence depending on the age (35% > 80 years old) [1].

Dizziness can be caused by a wide range of benign and serious conditions and it’s important to perform an accurate physical examination and radiological imaging to distinguish between cardiovascular, neurological and otological causes. Because 4 to 6 % of dizziness has a cerebrovascular origin (90% of cases secondary to ischemic lesions of the posterior brain circulation) a prompt diagnosis is a primary target for a better prognosis.

Case Report

We report the case of a 28-year old man, who came to our observation in the Emergency Department for objective dizziness, vomit, nystagmus to the right and anisocoria (left miosis). He had a negative pathological history and no home therapy. We performed a cranial CT which turned out negative (fig.1). An otholaryngologyst evaluation concluded for suspected vestibular neuronitis; after steroid therapy he felt better, and the patient was then discharged at home.

Figure 1- axial scan TC: any alteration

The day after he complained the persistence of dizziness associated with dysphonia, dysphagia, ataxia and paresthesias of left face and right body.Anisocoria was still present (left Horner syndrome). A second cranial TC with CTA showed a left vertebral artery dissection in the intracranial part (fig. 2 and 3).

Figure 2 Figure 3

Fig 2 and 3 axial scan TC with CTA: left vertebral artery dissection (the left artery’s caliber is reduced compared to the contralateral artery)

After a discussion of the case with neurologist and neuroradiologist we administered antiplatelet drugs and we transferred the patient to the Stroke Unit of Maggiore Hospital where an MRI showed a left bulbar ischemic lesion.

The patient was hospitalized in the Stroke Unit of Sant' Orsola Hospital where double antiplatelet therapy (clopidogrel and acetilsalicilic acid) was continued. A concomitant rehabilitation therapy was started and after some weeks the patient was discharged able to walk and to drink fluids.

Discussion

Ischemic events involving posterior cerebral circulation are frequent: they occur, in fact, in about 20% of all ischemic event and are caused by atherosclerosis, embolism and dissection of the large aortic arch, neck and intracranial arteries [2-5]. Arterial dissection is a common cause of posterior circulation stroke which usually involves the proximal extracranial vertebral arteries (ECVAs) just before they enter the foramen transversarium at C5 or C6, or in the very distal part of the artery in the neck before they penetrate the dura mater to enter the cranial cavity [6].

ECVA dissection usually causes vestibulocerebellar symptoms like dizziness, veering to one side, loss of balance and ataxia (when infarct involves the inferior portion of the cerebellum). The involvement of the intracranial part can cause vestibulocerebellar symptoms [7] and other symptoms as hypotonia of the ipsilateral arm, blurred vision or diplopia, nystagmus, ocular torsion and sensory symptoms (pain or unpleasant feelings in the face, loss of pain and temperature sensation in the ipsilateral face and in the controlateral trunk and limbs) [8].

Involvement of the nucleus ambiguus causes hoarseness and dysphagia.

Eventually contralateral hemiparesis is frequent in medial medullary ischemia; paresthesias or dysesthesias in the controlateral limb and trunk are described in ischemia of the medial lemniscus [7-9].

The occlusion of posteroinferior cerebellar artery or vertebral artery defines the "PICA syndrome" also called Wallenberg's syndrome (first described in 1895). This is the most common ischemic event of the encefalic trunk and it is characterized by a lot of symptoms and signs caused by a stroke of retro-olivar area. Usually it presents with ipsilateral Horner's syndrome, ataxia, facial loss of pain and temperature sensation and laryngeal muscles paralysis and controlateral hemiparesis and body loss of pain and temperature sensation.

The diagnosis is confirmed by neuroimaging findings (MRI or cranial CT with CTA) [10-12].

The available evidence suggests that treatment with thrombolytic therapy should not be withheld for eligible patients with very early acute ischemic stroke due to extracranial cervical artery dissection. Beyond the hyperacute period, antithrombotic therapy with either anticoagulation or antiplatelet drugs is accepted treatment for ischemic stroke and transient ischemic attack (TIA) caused by extracranial artery dissection, although there is controversy regarding the choice between the two [13]. There is controversy regarding the use of thrombolytics and antithrombotic agents for ischemic symptoms in patients with either intracranial dissection alone or intracranial extension of extracranial dissection because of the presumed increased risk of subarachnoid hemorrhage. Endovascular methods or surgical repair have been used to treat dissection, mainly for patients who have recurrent ischemia despite antithrombotic therapy [14].

The prognosis of cerebral and cervical artery dissection is related primarily to the severity of associated ischemic stroke or subarachnoid hemorrhage. In Wallemberg’s syndrome it' s usually good with a full recovery in 6 months.

Conclusions

Dizziness is a symptom that can be present in a variety of disease and its presence should lead to look for other neurological symptoms that can help to go on with necessary investigations for diagnosis. In our case, the association of anisocoria, dysphonia, dysphagia, ataxia and paresthesia led us to perform cranial CT with CTA so we reached the final diagnosis of vertebral dissection.